Process for removing defects from metal bodies



June 7, 1932. c. E. SPIGELMIRE ETAL 1,861,750

PROCESS FOR REMOVING DEFECTS FRO! IETAL BbDIES Filed Dec. 12, 1930 quent Patented June 7,1932

UNITED STATES CHARLES E. SPIGEIMIBE, OF SPABROWS POINT, AND ROBERT M. O!"

DUNDALK,.HABYLAND, ASSIGNORS 'IO BETHLEHEM STEEL COMPANY, A CORPORA- T1011 OF PENNSYLVANIA PROCESS FOR REMOVING DEFECTS FROI MEI.'AL BODIES Application filed December 12, 1930. Serial No. 501,898.

Our invention relates to a process for removing defects from metal bodies.

As is well known, steel blooms, slabs and other reliminary shapes of steel or iron, frei; have surface defects such as crevices, cracks and the like. To roll a bloom or slab without removing these surface imperfections would result in imperfect products. The mechanical working, such as rolling, in-

Volving a lmeading like manufacture, would cause the surface defects to become incorporated more deeply in the metal masswith consequent'weaknesses and defects of the steel structure. Accordingly it has been the prevailin practice to remove these surface defects rom the blooms or slabs by chipping.

- An operator with a pneumatic chipping hammer pro ressively chips away the surfacemetal w ich contains the defects.- Necessarily this is a slow process and involves a very substantial cost for labor;

ur process consists in removing the defects by burning away the metal which contains-it instead of by chipping it off.-

Obviously it is not broadly new with us to burn or, as is more commonly called, cut metal but, so far as we know, it is novel with us to remove imperfections in the surface of metal bodies by burning away the surface metal containing the imperfections.

Our method consists in directing a stream of oxidizing gas onto the surface of the metal to burn away the surface metal which ineludes the defect. An important feature of our method is in so burning away the portion of the metal containing the defect as to produce a depression which merges gradually into the surrounding unburned metal, that is 40 to say, a depression which gradually diminishes indepth toward the surrounding unburned metal; contrasting with the ordinary cutting efiects where a kerf is produced which does not taper-off gradually in depth but is more or less abrupt having steep sides. If in removing defects kerfs were to be formed, as in the ordinary cutting operations, with the sharply abrupt sides, it would be difiieult, if not impossible, to prevent the edges of the kerfs being folded over the cuts during the rolling operations and defects produces its most intense burning action centrally thereof gradually diminishing outwardly therefrom whereby the graduall rounded depression in the metal is produce This flaring stream of oxygen for burning out the defects is conveniently produced by passing the oxygen through a burner tip, the

oxygen passageway of which flares or widens as it approaches the surface.

Referring to the drawing, which illustrates a tip which is suitable for this purpose:

\ Fig. 1 is a longitudinal section through the tip, taken on the line 11 of Fig. 2; and

Fig. 2 is an end view of the tip.

This'tip includes the body portion 11 and the screw threaded shank portion 12 whereby the tip may be screwed to a blow torch in the well known way. a

Extending centrally and longitudinally of the tip is the oxygen assage 13 having a flaring portion 14. isposed around the oxidizing gas passage is a plurality of pass'ageways 15 through which a mixture of combustible and oxidizing gas may pass as,

for example, oxygen and acetylene.

in the usual way, oxidizing gas passage 13 communicating with the oxygen passage of This tip may be attached to a blow torch PATENT OFFICE the torch and gas mixture passages 15 communicating with the gas passages thereof.

The torch may be employed in the customary way so far as the control and use of oxygen and fuel gasses are concerned; The distinctive characteristic of the tip is the flaring portion of the oxidizing gas passageway at its outer end, whereby the stream of oxygen as it issues from the tip widensand thereby producesa less intense effect marginally of the stream. As a'consequence the metal is burned away in amounts gradually diminishing outwardly from the central portions of the oxygen stream. Naturally this avoids the shar edges which are produced by cutting wit themeans heretofore emp 0 ed.

Iii burning away the surface metal, which includes the defect, the stream of oxygen is directed against the metal surface in a direction inclined thereto. If a seam, for example, is being removed, the torch is so held that the stream of cutting oxygen issuing from this ti'p"is inclined to the surface of the metal and substantially in line with the direction of the seam. In View of the fact that the stream of 0 gen flares or widens, the efiects of the burning stream diminishes adually in amount toward the adjacent unurned metal; thus producing a relatively wide, shallow depression which diminishes gradually in depth toward its sides. Having thus escribed our invention what we claim as'new'and desire to secure by Letters Patent is 1. In a process for removing imperfections from metal,'the steps of heating the metal tov a kindling temperature and directin 0 gen onto the'su'rface of the heated me to u'rn away the'metal including the imperfect structure; such burning diminishinggradually in;a-mo'u nt toward the adjacent unburned metal surface:

2. In a process for removing imperfections from metal, the steps; of heating the'metaltq a kindling temperature and directing oxygen onto the surface'of the heated metal to burn away the metalincluding the imperfect structure to produce a. shallow depression di minishing sides. s 'i 3. In for removing and like defects from metal, the steps of heating the metal we, kindling temperature and'diL- recting oxygen in a'flaringstream on to the surface of the heated metal at an inclinaour signatures. r

tion to thesurface of'the metal and inthe general direction of the'seam,

In testimony wh e'reef' we hereunto afliit CHARLES SPIGELMIRE.

gradually in depth toward its 

